Ammunition for trench mortars



Oct. 5 1926. l0237 L. N. D. MIXSELL AMMUNITION Fox TRENGH MoRTARs Fied Feb. 5. 1924 Patented oa. 5, (11926.

UNITED STATES PATENT OFFICE.

LEIGETON N. D. MIXSELL, OF BETHLEHM, PENNSYLVANIA, ASSIGNOB T BETHLEHEM STEEL COMPANY.

.AMUNITION FOR TRENCH MORTARS. i

Application vled February 5, 1924. Serial No. 690,726.

My invention relates to mortars, more particularly of the trench type, and it has for an object to rifle or provide the mortar bore with interior helical grooves and to provide ,the projectile with lands to fit the grooves or rifling, whereby the projectile may be loaded at the muzzle in the usual way and whereby, upon firing, spinning motion is imparted to the projectile in order that the direction of ring may be more accurately controlled.

A further object of my invention is to provide a separable base member for a mortar projectile, such base member having an upper or main propellantl charge chamber and lower supplementary propellant charge chambers communicating with the upper chamber and extending through the bottom of the base member, whereby the amount of supplementary charge may be readily and quickly varied by the gunner to suit conditions.

A further object of my invention is to provide a projectile base member with main and supplementary propellant charge chambers together with charges enclosed in inflammable envelopes or capsules, whereby the base member may be quickly and accurately charged and whereby the amount of the supplementary charge may be readily varied in the field. f

A- further object of my invention is to provide a base member for a projectile of the type referred to with main and supplementary propellant charge chambers, together with a primer opening so that a mortar may' be loaded in the usual manner and fired whenever desired.

A further object of my invention is to provide. a mortar projectile with a base member having lands and a circumferential groove near the bottom which'intersects the j lands to provide lugs behind which tit lugs lof a weather-proofl cap, the latter fitting against the bottom of the base member to protect the explosive propellant charge while the projectile is being transported.

These and other objects are obtained by my. invention as will be hereinafter pointed out in the 4specication and set forth in the 50 claims.

Apparatus made in accordance with my invention is illustrated, by way of example,

vin the accompanying drawin s, forming a part of this application, in w ich Figure 1 is a sectional view of a mortar incorporating my improvement and showin a projectile therein having my improve base member;

Figure 2 is a side elevation of my im- 60 proved projectile;

Figure 3 is a longitudinal sectional view of the projectile shown in Figure 2;

Figure 4 is a sectional view taken along the line IV-IV of Figure 3 and showing 65 Ehe protective cap applied to the base mem- Figure 5 is an end elevation of the apparatus illustrated in Figure 3 and showing the protective cap; and

Figure 6 is a detail view illustrating a protective cap suitable for use with my 1mproved projectile.

Referring now' to the drawings more in detail, in Figure 1, I show a mortar 10 of 75J .conventional type held in place by suitable supports-11 and 12. The bore of the mortar 10 is provided with a plurality of helical grooves 13 within which are adapted to slide lands 14 carried by the base mem- 80 ber 15 of a projectile 16.

Referring to Figures 2 and 8, the projectile 16 includes a base member 15 and an explosive shell portion 17, the base member 15 being preferably provided with an S5 interiorly threaded wall portion 18 `adapted to fit over a threaded projection 19 on the explosive shell portion 17.

The base member 15 is generally cylindrical in form and it is provided with lands 14 already referred to, such lands fitting the spiral grooves or riiies 13 of the bore of the-mortar in order that spinning motion may be imparted tothe projectile 16 as the latter is expelled from the mortar. The lands 14 are preferably helical, although this is unnecessary provided suiiicient windvage orclearance exists between the sides thereof and the sides of the helical grooves. A main propellant charge chamber 20 is arranged within the base member and it communicates with supplemental'y propellant charge chambers 21 which extend through the bottom of the base member. A primer opening 22 extends through the bottom of the base member and communi;-

cates with the in ain propellant charge chantber 20.

The main propellant charge chamber 2O and the `supplementary charge chambers 21 are preferably made cylindrical in form to receive charges enclosed in infiammable cap- Vsules, the capsule for the main charge 23 being indicated at 24 and the capsules for the supplementary charges 25 being indicated at 26. The amount of the supplementary propellant charge may, therefore, be`

kthis position, a primer of any suitable type in the primer opening 22 may be operated upon through the firing opening 26 at the breech end of the mortar to explode the main propellant charge; and, if there is a supplementary propellant charge, the latter will be exploded from the main charge. When the 1propellant charge or charges is or are exp oded, the generated gases pass rearwardly through the openings 21 and react against the breech end of the mortar to expelA the pro'ectile therefrom.

The base mem er 15 is adapted to receive a cover 28 which protects the propellant charges while the projectile is in transport or 1n storage. To this end, I have provided a novel arrangement of the base member to rece1ve-a cap of Well-known design.

Referring to Figures 2 and 3 it will be seen that the lands 14 are intersected by a clrcumferential groove 29 so as to provide terminal lugs 30. The cover 28 has inwardly-extending lug or hook portions 31 which are adapted to fit between the lands; andupon turning the cover to asulicient extent the lugs or hook portions 31 may be brought in position to engage behind the lugs 30 to hold the cover in lace.

The cover 28 is lined wit any suitable resilient material which effects a tight seal with respect to the base member 15 and which at the same time is of such a character as not to affect the propellant charge. -Such a 1min is indicate at 32 in Figures 3 and 6, and have found cork to be suitable for this purpose. The'lugs or hook portions 3 1 fit` the lugs 30 with a suiiicient degree of tightness and the lugs or hook "portions 31 are sutiiciently resilient so that the cap 28 is pulled to seat its lining 32 tightly against the bottom of the base member.

From the foregoing, it will be apparent that lI have devised a mortar which is safe from the standpoint that it is not automatically fred upon the projectile reaching the breech end and one inwhich a better degree of direction of control may be exercised due to the rilied effect. Also the arrangement of propellant charge chambers is such that charges put up in inflammable capsules, such as 'capsules of pyralin, may be readily inserted into the chambers, this feature being particularly advantaveous in that a gunner may readily vary the supplementary charge to meet conditions. The lands are made to serve another purpose in that they are notchednear the bottom of the basel member to provide lugs to receive lugs of a. cover.

While I have shown my invention in but one form, it will be obvious to those skilled inthe art that it is not so limited, but is susceptible of various other changes and modifications Without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed there- Vupon as are imposed by the prior art or as are specifically set forth in the appended claims.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is 1. A. projectile for mortars including a base member having an intermediate explosive charge chamber and a plurality of supplementary explosive charge chambers communicatin with the rst chamber and extending trough the bottom of the base' member. v

2. A projectile for mortars including a base member having its upper end interiorly threaded to t threads onta shell-V member, said base member having an interior cylindricalchamber and a plurality of supplementary cylindrical chambers communicating with the first chamber and extending throu h the bottom of the base member.

3. projectile for mortars including a base member for attachment to a shell, said base member including an upper main explosive charge chamber, a plurality of openings communicating with said chamber and extending through the bottom of said base member, said openings being adapted for the reception of supplementary charges, and a primer opening extending through the base member and communicating wlth the chamber.

4. A projectile for mortars including a base member for attachment toi a. shell, said base member including a 'central upper chamber and lower chambers communicating with the upperchamber and extending iso throughl the bottom of the base member, an lands being notched, and a ca having in- 10 inflammable envelope containing an explowardly-projecting lugs adapte to pass over siveocharge in the upper chamber, and one the base member between the lands and to or more inammable envelopes containing engage in the notches of the lands upon 5 explosive charges in the lower chambers. turning of the cap to hold the latter in place.

5'. A projectile for muzzle-loading mortars In testimony whereof I hereunto affix my 15 including a base 'member having exterior signature this 30th day of January, 1924. lands and an interior charge-receiving chamber extending through the base member, said i LEIGHTON N. D. MIXSELL. 

